A beautiful skin is a great desire to every woman. In order to maintain the healthy condition of a skin as well as make the skin more beautiful and maintain a rich luster, basic cosmetics and makeup cosmetics are widely used.
It is requested to evaluate, by some method, how beautiful a skin has turned or how lustrous a skin looks by maintaining the healthy condition of a skin or using appropriate cosmetics. In particular, there is an earnest request for a method to readily evaluate the degree of beauty or luster of the skin of a test subject at a cosmetics counter in a department store, a drugstore or a cosmetics store.
Beauty of a skin has been evaluated by visually performing a sensory evaluation, for example, by way of paired comparison. In this approach, a target of comparison is mandatory. It has been difficult to represent the beauty of a skin by way of some physical means in the absence of a control for comparison.
The luster of a skin surface is a key element for representing the health, beauty, or post-makeup finish of the skin. Thus, it is one of the key purposes of a basic cosmetic and a makeup cosmetic to provide a skin with a proper luster.
In order to develop a cosmetic having such effects, it is necessary to objectively measure the gloss of a skin that corresponds to the luster of a skin.
The gloss of a skin, influenced by the properties of a skin as a substance as well as sebum, a makeup film or the shape of a skin surface, is sometimes judged as “facial shine” that gives bad impression. It is thus less objective to evaluate the luster of a skin by way of a first-dimensional value alone such as the glossiness.
A prior art method is known for judging and evaluating the “facial shine” or “appearance of sebum”. The method picks up the image of a skin with the skin surface under high contrast to obtain image data, distinguishes bright pixels that exceed a predetermined threshold and dark pixels that is below the threshold to obtain the number of bright pixels and the percentage of the area occupied by the bright pixels (refer to JP-A-3236731).
This method solely measures the glossiness of a skin, with the result varying with the way the threshold value is determined, so that it is hardly capable of evaluating the luster or beauty of a skin from an objective point of view.
Further, the health, beauty or post-makeup finish of a skin of a face or the like is a major concern to many women. A woman may wish to know the details of how the overall appearance of her skin would change by improving the health of her skin, such as skin problems or by using a cosmetic. The answer is not given until the health of her skin is improved or the cosmetic is actually used.
Unlike this approach, a casual method is used for showing the appearance obtained in case the health of a skin is improved or the appearance obtained in case a cosmetic is used by using a photograph of an actual model. However, with the method, only the changes in appearance of the model can be observed, and not the user him/herself.
In view of the foregoing circumstances, it has been requested to provide an evaluation method capable of objectively measuring the luster or beauty of a skin and giving an evaluation similar to the one by an observation with naked eyes.
Further, it has been requested to provide a method for simulating changes in the appearance of a target such as a human face by simply changing the roughness of a texture or the like of the target at a cosmetics counter in a department store, a drugstore or a cosmetics store.